How to set an embedded data variable as an average of other embedded data variables

Hello, I am currently having issue getting this bit of code working. I am trying to take the average of four other embedded data variables, all of which are calculated during the survey.
I have four questions on one page that ask for the four values ("holdtoground1" etc.) to take the average of. Here is an example of the javascript for one of them:
Qualtrics.SurveyEngine.addOnPageSubmit(function() {
var answer = document.getElementById('QR~' + this.questionId);
    Qualtrics.SurveyEngine.setEmbeddedData( 'holdtoground3', answer.value );
});
On the fourth question, I also use javascript to calculate the average of these four variables ("holdtogroundBL"), which I think is where the issue is.
Qualtrics.SurveyEngine.addOnPageSubmit(function() {
var answer = (document.getElementById('QR~' + this.questionId)).value;
    Qualtrics.SurveyEngine.setEmbeddedData( 'holdtoground4', answer );
//calculate overall hold to ground time
var item1 = parseInt("${e://Field/holdtoground1}");
var item2 = parseInt("${e://Field/holdtoground2}");
var item3 = parseInt("${e://Field/holdtoground3}");
var sum = item1 + item2 + item3 + answer.value
var average = sum / 4.0;
    Qualtrics.SurveyEngine.setEmbeddedData( 'holdtogroundBL', average);

});
The problem is that I want to show the user that average on the next page, so after a page break I have displayed text that looks like this:
But, while the four smaller variables load, the average does not:
Can anyone tell me what my issue is? I made sure to set all the embedded data variables as Numbers, and even have them default to 0.